Dynamo and dynamo installation



June 22, 1937. A.'V. E. c. GUILBERT 2,034,527

DYNAMO AND DYNAMO INSTALLATION I Filed Sept. 21, 1933 Patented June 22, 1937 PATENT OFFICE 2,084,527 DYNAMO AND DYNAMO INSTALLATION Andr Vincent Ernest Cyrille Guilbert, Paris,

- France Application September 21, 1933, Serial No. 690,402

In France September 24, 1932 3 Claims.

The invention relates to improvements in installations employing dynamos of the three-brush type and in the construction and arrangement of such dynamos themselves.

Dynamos cf the three-brush type possess the well-known property of giving a constant output current for a relatively wide scale of speeds, on the condition that the voltage at the terminals is exactly determined and maintained at a constant value, such as by means of a battery of accumulators. This property is obtained by means of a shunt excitation connected between a normal brush corresponding to a neutral line and an auxiliary brush mounted at the same level as a conductor situated beneath'the leading pole tip of the succeeding pole.

The distortion of the charging magnetic flux, due to the transverse reaction of the armature, which is variable for a same current in the armature' with the value of this flux, causes, for a same voltage at the terminals of the dynamo, a progressive reduction in the voltage of the excitation current when the speed increases, whence the desired regulating effect on the output current.

It is thus necessary to obtain equalitybetween M the power of the dynamo, the charging power of the battery and the power required under permanent working conditions.

One object of the present invention is to avoid the use in such installations of a dynamo such as defined above Other objects and advantages of the present invention, together with particular constructional details of various embodiments thereof, will be more clearly understood from the following desimplified form of realization of the compensating means.

It will be seen from the following that the invention permits of utilizing a dynamo having a power which is greatly superior to thecharging power of the battery, of obtaining under perma.

nent operating conditions from the two circuits the whole of the power which can be furnished by the dynamo and of only requiring from the latter,

when no consuming device is in use, the charging power of the battery. I

. flowing in the second circuit ,8.

Referring to the hitherto proposed arrangement of Fig. 1, the normal brushes of the dynamo are shown at I, the third brush at 2, the inducing windings at 3, whilst 4 is the consuming circuit and 5 the battery of accumulators. In the arrangement according to the invention of Fig. 2, however, there is provided a second consuming circuit 6 and in series therewith a compensating winding I mounted on the field'poles 8, as shown more particularly in Figs. 3 and 4, ami which is intended to neutralize the effects of the transverse reaction of the armature for the current The brushes I, mounted on the neutral line, and the third brus 2 which is out of line with regard to the brushes I, are arranged in the same manner in Figs. 1 and 2, as well as the inducing windings 3 and the first consuming circuit 4, with which are mounted in parallel the dynamo and the battery of accumulators 5, and a make-and-break device 9 is provided for disconnecting the dynamo from Theoretically, the compensation is obtained in a well-known manner by arranging in slots I0 provided in the pole pieces a distribution of ampere turns which is identical but opposed to that of the armature. Fig. 3 shows clearly the manner in which this method of winding is obtained. In this figure, the numerals I, 2, 3, 4, 5, 8, 'I, 8 and 9 indicate the same parts as in Fig. 2. It will be seen that the compensating winding I is provided in slots III formed in the faces of the pole pieces 3 adjacent the air gap between the pole pieces 3 and the armature of the dynamo. vThe part II of the compensating winding is electrically connected to the circuit 4 by the conductor II, and to the part I2 of the winding I by the conductor I2. The part I2 is connected to part I3 by the conductor I3, the part I3 is connected to part I4 by the conductor I4 and the part I4 isconnected to the circuit 8 by the conductor I 5. The arrows indicate the direction of the currents in the parts of the compensating winding and in the conductors of the armature.

It is known in effect that the transverse reaction of the armature weakens the field in the air gap under the leading pole tips of the poles singlewinding I] on the pole, this-winding H, g

passing through a single slot I! as represented in Fig. 4.

The increase in the fiux at the level of the trailing pole tips caused by the e of the current of the second'circuit 6 in the armature and due to the absence oi compensation in this place is not considerable, even at great speeds, due tothe saturatba oi the teeth poi armature under these pole tips and the increase in the electromotive force of the dynamo which results therefrom permits of reducing somewhat the compensating ampere turns of the windings I] of Fig. 4. The compensation thus established is thus doubly economical and constitutes an important improvement according to the present invention. It is not necessary that compensating windings should beplacedonallofthepoles It will be realized that the comparison of the partial compensation to a sort of compound connection only relating \to a traction of the pole piece should be avoided. A classical compound connection relating to the whole of the pole has I for object to render the functioning of the threebrush dynamo theoretically independent of the current flowing in the second circuit for a single speed in the neighbourhood of which this last solution although imperfect may be considered acceptable.

It willbe understood that the embodiments 40 above described have been given by way of example and that the invention is only limited insofar as is necessitated by the prior art and the M spirit of the appended claims. I claim:

Llncombinatiomadynamoeqiflppedwitha pair of main brushes and a third brush, and having pole pieces excited by windings shunted across one of said main brushes and said third brush, a

' first consuming circuit fed by said main brushes 'pensating winding connected in series with said second circuit and-disposed in slots on the faces oi said polepieces at least in the region of the I leading pole tips.

2. In combination, a dynamo equipped with a 15 pair of main brushes and a third brush, and having pole pieces excited by windings shunted across one. or said main brushes and said third brush; a first consuming circuit ied by said main brushes and containing a source of voltage, a second con- 20 suming circuit in parallel with the first but containing no source of voltage, and means for neutralizing that portion of the armature re-action which is due to the current flowing in said second consuming circuit, said means comprising a com 25 pensating, winding connected in series with sai I second circuit and distributed in slots over th faces oi said pole pieces.

3. In combination,'a dynamo equipped with a pair 01 main brushes and a third brush, and hav- 30 ing pole pieces excited by windings shunted across one of said main brushes and said third brush,

a first consuming circuit ied' by said main brushes and containing a source of voltage, a second consuming circuit in parallel with the first but con- 35 taining no source of voltage, and a compensating winding in series with said second circuit and disposed adjacent the air gap between said pole pieces and armature, said compensating winding being so proportioned and arranged that the 40 ampere turns due thereto are substantially equal but opposed to those due to the fiow of the same current in the armature. I ANDREVINCENT ERNEST cvmmm: GUILBERT. 

